Shadowgraphic studies of DLC film deposition process in dense plasma focus device

The 3.3-kJ dense plasma focus (DPF) device is used to deposit diamond-like carbon thin films by ablating the high purity graphite fitted to the top of the anode. The plasma focus dynamics was observed using shadowgraphic method to confirm the symmetrical current sheath dynamics and to outline the thin-film deposition process in DPF device. Shadowgraphic results showed that the profile of current sheath remains symmetrical in axial as well as radial collapse phase even for the graphite fitted anode. The ablation of the graphite top was found to start about 50-70 ns after the first peak on voltage probe signal and continued for more that 1 μs. The deposited films have been analyzed for their structure, composition and bonding characteristics. The effect of number of DPF shots and angular position of the substrate on Raman spectra of deposited films was analyzed in terms of Raman peak intensities and positions. The surface composition of the deposited films was obtained using X-ray photoelectron spectroscopy and is explained on the basis of film deposited conditions and ion emission characteristics of the plasma focus device.